Special Issue "Emergence in Chemical Systems"

Guest Editor
Dr. Pierre-Alain Monnard
FLinT center, Institute for Physics and Chemistry, University of Southern Denmark, Campusvej, 55, 5230 Odense M, Denmark
E-Mail:
Phone: +45 6550 4437
Fax: +45 6615 8760
Interests: self-replicating chemical systems and protocells; interface catalysis and membrane chemistry; microcompartmentalization; non-enzymatic polymerization; RNA world

Dear Colleagues,

The concept of emergence in chemical systems is challenging to define. In general, the term refers to phenomena in which the structures and behavior of multicomponent systems exceed those predicted from knowledge of the individual components. Entropy is at the core of emergent properties, driving essential processes such as self-assembly of lipid bilayers and folding of macromolecules, as well as molecular recognition.

The first appearance of living systems on the early Earth can be understood as an emergent phenomenon, because the simpler progenitors of living cells referred to as protocells were composed of a self-assembled collection of molecules that by themselves were non-living, yet together exhibited properties of self-maintenance, self-reproduction and evolution.

Because such system-level processes also occur in simpler chemical assemblies, emergence can be studied in model systems that display functions similar to those of living systems. Examples of such systems include dissipative structures like those generated by the Belousov-Zhabotinsky reaction, and molecular networks that consume energy and resources to achieve cooperative growth and self-replication, as well as to react to external constraints.

Studies of such systems conducted both in laboratory settings and in silico are leading to a deeper understanding of the complexity underlying emergent properties. This special issue of Entropy provides a repository for information, research and insight regarding emergent phenomena in chemical systems.

Pierre-Alain Monnard
Guest Editor

Submission

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are refereed through a peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Entropy is an international peer-reviewed Open Access monthly journal published by MDPI.

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• emergent properties
• chemical systems
• self-assembly
• self-replication
• self-maintenance
• metabolism
• molecular networks
• dissipative structures
• protocells
• minimal cell
• logic gates
• motility
• evolution
• adaptation
• energetics

Type of Paper: Review
Title: Recent Advances in the Chemistry of the Para-Acyl Calix-Arenes: From Nano-Capsules to Macro-Films
Authors: Anthony W. Coleman ¹, Said Jebors ¹ and Kinga Suwinska ²
Affiliations: ¹ IBCP CNRS, Univ. Lyon 1, Lyon, France; E-Mail: anthony.coleman@adm.univ-lyon1.fr (A.W.C)
² IChF, PAN, Warsaw, Poland
Abstract: The para-Acyl calix-arenes, amphilphilic molecules having 4, 6, 8 or 9 phenolic units in the calix-arene macrocycles have molecular sizes ranging between 1x1x1 nm to to 4x4x2 nms. Easily synthesized in multi-gram quantities they are also relatively simple to fully or partially substitute at the phenolic face in a controlled manner. Thus a wide range of physical properties can be built into the molecules.
They are capable of assembling into a variety of two and three dimensional structures, in the solid state, as colloidal dispersions and at the air-water interface. In the solid state for the calix-4-arene systems non-porous solids composed of van der Waals capsules have been observed and are capable of absorping gas molecules with certain selectivity. Also in the solid state the molecules may assemble into structures modeling reverse micelles. For the larger calix-arenes self functionalisation can occur with folding to produce transmolecular channels.
In the colloidal state extremely stable, non-toxic solid lipid nanoparticles can be prepared. Such systems are capable of encapsulating and transporting bio-active molecules, while being non-toxic.
Certain systems are capable at the air-water interface of forming large, 5x5 cm square films of micron thickness and which are mechanically stable. The structure of these films is totally fascinating as they are formed by the assembly of highly mono-disperse nanoparticles form by the non-covalent assembly of the molecules. The films are stabilized at the exterior by nanometer thick molecular assemblies.